Wisconsin and IL law enforcement attempted to stop the bus after a passenger called 911, officials said.
"It nearly felt like a terrorist situation". With guns drawn, police took the suspect into custody.
However, he continued to make threats to the deputies taking him to jail as well as Racine County investigators who interviewed him, Schmaling said. Schmaling said the driver didn't know there was any potential danger.
The man allegedly made threats to kill people as the bus was traveling from Milwaukee to Chicago, according to the Racine County Sheriff's Office. He works at a restaurant in Milwaukee and was returning to Chicago, Schmaling said, when he apparently got into an argument with other passengers. "You're on a bus with a guy who said he had a gun", said Dodd.
The bus eventually stopped on I-94 at Rt. 173.
But the sheriff's office is going to continue to search it and piece together stories from the witnesses on board.
No gun was recovered on the bus.
New footage in Zainab case could frustrate probe
Regional Police Officer (RPO) Kasur Zulfikar Muhammad confirmed that the girl was strangled to death. Zainab Ansari's body was found in a rubbish dump on Tuesday, several days after she went missing.
So far no injuries have been reported.
"(He) has been in our country illegally and has been deported some time ago back to Mexico and by virtue of his actions last night, he's back and threatening to kill Americans", Racine County sheriff Christopher Schmaling said.
"Hopefully at the end of the day this individual is held accountable for his actions and ultimately brought to justice", Schmaling said.
The caller advised that he was a passenger on the Greyhound bus that was en route to Chicago.
He also commended the Kenosha County Sheriff's Department, Wisconsin State Patrol and Illinois State Police for their assistance.
The incident led to a full freeway closure of southbound I-94 at Highway 50 in Kenosha County.